A 17-year-old boy with a semiautomatic pistol walked up to an 18-year-old man Friday night in the Little Village neighborhood, pointed the weapon toward his face and squeezed the trigger, police said.

Within minutes, someone else who had seen the shooting shot the 17-year-old with a shotgun, police said, and both young men shot were in critical condition at Mount Sinai Hospital.

Police said the two were found lying near each other in the 2600 block of South Ridgeway Avenue about 10:10 p.m. Both identify with conflicting gangs and were shot on a street painted with graffiti from those gangs, which use Ridgeway as a border.

The boy shot the man between two parked cars, then soon after the second attacker came up to the boy and shot him on the grass in front of the same address, according to police. When police arrived, they found the semiautomatic handgun lying next to the boy.

Two neighbors said there had been shooting the night before in the same block but nobody was hit.

The two shot on Ridgeway were among at least 15 people shot since Friday afternoon, two of whom died. A third person was killed in Chicago since yesterday afternoon – a 75-year-old man was found dead with head trauma inside his home about 9:50 p.m. in the 5600 block of South Racine Avenue in the Englewood neighborhood.

The man, identified as Alameen Muhammad, of the Racine Avenue apartment building, died from blunt force trauma to the head in an assault, and his death was ruled a homicide by the Cook County medical examiner's office following an autopsy today.

Police were called to the home after a man who works for Muhammad was unable to reach him, then went to the apartment building he owned and lived in, according to a police report. The employee found the building's back door and the 75-year-old's truck unlocked and parked in back of the building.

The employee found Muhammad's apartment locked, so he climbed a fire escape and saw the man on the floor in the bathroom, according to police. The employee forced his way into the apartment and called 911 after he found Muhammad.

Earlier Friday afternoon, a 3-year-old girl alerted neighbors to the shooting of her 23-year-old stepfather at a family home in the Morgan Park neighborhood.

The man was dead from a gunshot wound to the head in the 1100 block of West 111th Place, said Chicago Police Department News Affairs Officer Veejay Zala. Police were called to the scene about 3:10 p.m. and found the man dead.

The man was identified as Kyle Hogan of 11800 S. Campbell Avenue, according to the Cook County medical examiner's office. He was declared dead on the scene at 3:40 p.m.

The girl was believed to have been at the home at the time of the shooting, a source said. The man shot to death is not believed to live there, but another relative does. After the shooting, she went next door and told neighbors that the man had been shot.

Family members confirmed to WGN-TV that the girl went next door after the shooting.

The neighbors went next door and found Hogan on a couch in the living room, family members told WGN-TV. When police arrived on scene, they found the man on the couch, shot in the face, a source said.

Police were checking for possible video evidence.

Hogan's aunt and other family members said that her brother, age 40, was shot on the Southeast Side recently, and is still hospitalized.

Two people were shot about 11:30 in the 1800 block of North Pulaski Road in the Hermosa neighborhood and a third person was pistol-whipped. A man in his 40s died from the shooting at Mount Sinai Hospital and the second person shot, a 27-year-old man, is in serious condition at Advocate Illinois Masonic Medical Center, police said.

The three, who were at a party involving co-workers, were attacked by a co-worker after an argument over beer and the shooter was arrested at the scene, police said. A spokesman for the Cook County medical examiner's office did not release the dead man's name Saturday morning.

In other shootings:

• A 22-year-old man was shot about 5:30 Saturday morning in the 5100 block of West Chicago Avenue in the South Austin neighborhood on the West Side, police said. The man was sitting in a vehicle stopped at a stoplight at Chicago and Laramie Avenue when a male approached on foot and fired a gun at him. The 23-year-old man was hit on his left side and was transported in critical condition to Mount Sinai Hospital.

• A boy in his teens was shot about 5 a.m. Saturday in the 4000 block of West Grenshaw Street in the Lawndale neighborhood on the West Side. He was hit in the hand and foot and is in stable condition at Mount Sinai Hospital, Greer said.

• About 3:45 a.m. a 24-year-old man was shot in the leg while he stood with a group of people outside a home in the 1700 block of West 19th Street in the Heart of Chicago neighborhood on the South Side. He was taken to John H. Stroger, Jr. Hospital of Cook County, Greer said.

• Another man was shot about 1 a.m. in the 5000 block of West Superior Street in the South Austin neighborhood on the West Side. The 26-year-old was standing in a group and told police he heard shots and felt pain. He was taken to Mount Sinai Hospital in good condition, police said.

• Two people were shot in the South Austin neighborhood about 11:05 p.m. in the 4800 block of West Walton Street. They were shot near the corner of Cicero Avenue and Walton Street and taken to West Suburban Medical Center in good condition. A 16-year-old girl was shot in the leg and taken in an ambulance and a 21-year-old man showed up at the same hospital with a leg wound, police said.

• About 3:15 p.m., a 23-year-old man walked into Holy Cross Hospital with a gunshot wound to the wrist, Zala said. He had been shot in the 7100 block of South Kedzie Avenue in the Marquette Park neighborhood.

• About 3:07 p.m., a 30-year-old man was shot in the leg in the 5900 block of South Spaulding Avenue in the Chicago Lawn neighborhood. He was stabilized at a local hospital, police said.